1. Field of the Invention
The present invention relates to an overload control device and a method thereof in a mobile communication system, more specifically to an overload control device and a method thereof in a radio network controller.
2. Description of the Related Technology
A mobile communication service has been continuously developed since the first generation mobile communication service mainly having a low-quality voice call service provided by the advanced mobile phone service (AMPS) of an analog cellular type, which started in late 1980s.
In the second generation mobile communication service, it was possible to provide an improved voice call service and a low-speed (14.4 Kbps) data service by the global system for mobile (GSM), the code division multiple access (CDMA) and the time division multiple access (TDMA) of a digital cellular type.
In the 2.5th generation mobile communication service, it was also possible to provide an improved voice call service and a low-speed (144 Kbps) data service by developing the personal communication service (PCS) that can be internationally used in addition to acquiring frequency bands having the unit of GHz.
The third generation mobile communication service can be distinguished into two systems. One is the mobile communication system of an asynchronous type based on the generation partnership project (3GPP). The other one is the CDMA-2000 system of a synchronous type based on 3GPP2. Especially, in the mobile communication system, which is the wireless protocol suggested in the IMT-2000, is being provided or prepared by a lot of worldwide communication service providers.
The mobile communication system, which has a high quality call service and uses a band diffusion method, is suitable to transmit a lot of data.
The WCDMA communication method employs the adaptable multi-rate (AMR) for voice coding and supports high mobility that can make it possible to call to each other at a speed of 100 km/h.
The WCDMA communication method is also employed by most countries. Technical specifications for the WCDMA is continuously developed in the 3GPP constituted by many institutes in Korea, Europe countries, Japan, USA and China.
Typically, service providers or network operators provides different users with various multi-media data services and/or voice communication services.
To provide the data services and/or the voice communication services, the service providers or the network operators manage wireless sources including system capacity and processing amount.
A mobile communication terminal can access a communication system and a different mutually accessed remote control communication system. Each area covered by radio networks are typically referred to as a cell. Each radio network is set to receive an electromagnetic wave at a pilot output level in which it is enough to cover the cell. The pilot channel is downlink-broadcasted to make it possible to recognize cells and to measure received levels.